The sentencing phase of Dzhokhar Tsarnaev's trial began Tuesday, and the jury must now decide whether the man convicted of co-orchestrating the Boston Marathon bombing in 2013 should be put to death or spend the rest of his life in prison.

Tsarnaev, 21, was found guilty by a federal jury earlier this month on 30 counts related to the bombings that killed three and injured more than 260, according to CNN. The penalty phase of the trial could last as long as four weeks.

According to a new CNN/ORC poll, 53 percent of Americans think Tsarnaev should be put to death, while 45 percent believe he should be sentenced to life in prison. The poll found that non-college educated pollsters feel more strongly about the death penalty (59 to 48 percent), and that whites are more likely to vote for capital punishment (58 to 43 percent).

Residents in the Northeast were more in favor of executing Tsarnaev (58 percent) than the rest of the country (52 percent).

In comparison to the 53 percent of Americans who are in favor of the death penalty, CNN reported that 64 percent of citizens wanted Oklahoma City bomber Timothy McVeigh executed in 1995.

Kevin Corcoran, whose wife lost both her legs in the attack, argued in favor of the death penalty, the Globe noted. Celeste Corcoran was the first witness to testify for the prosecution in Tsarnaev's penalty phase Tuesday, according to BuzzFeed News. She told the jury that she moved closer to the finish line to see her sister complete the marathon when one of the bombs went off.

"Then our whole world exploded," Corcoran testified, saying that the blast threw her in the air. "It was like this deafening silence. I just remember lying there . . . thinking, like, what was that? . . . I just remember seeing so much blood where my legs were."

While Tsarnaev's defense attorneys opted until next week to make their opening statement, federal prosecutor Nadine Pelligrini said in hers that Tsarnaev was "unrepentant, uncaring, and untouched . . . by the sorrow he has created," BuzzFeed noted.

The sentencing phase of Dzhokhar Tsarnaev's trial began Tuesday, and the jury must now decide whether the man convicted of co-orchestrating the Boston Marathon bombing in 2013 should be put to death or spend the rest of his life in prison.